Study On Damage Machanism And Scope Of Deep Roadway Under Mining Blasting

As underground mining continues to develop in depth,the higher initial stress and blasting force superposition produce a higher stress environment.In this environment,the following problems have arisen,the surrounding rock pressure is exacerbated,the rock burst frequently occurs,the engineering is frequently unstable,and partition rupture occurred in the surrounding rock.At the same time,as an important part of underground engineering,the roadway is very important for its safety and stability in mine production.Under this background,how to control the damage range of underground roadway and how to carry out reasonable and scientific support to the roadway have become an important issue in underground engineering research.Taking the Zijinshan gold and copper mine in Fujian Province as an example,this paper uses theoretical research,numerical simulation and outdoor test methods to study the damage mechanism and influence range of deep roadway under the influence of blasting.The main contents and achievements are as follows:In the aspect of theoretical research,firstly,the current damage theory is analyzed and the KUS damage theory model is selected as the basic damage model.The evolution mechan ism of fracture damage under rock under high stress is studied,and the theoretical model of crack distribution is obtained.The fracture mechanism of the crack in the coupled environment of blasting load and in-situ stress was studied and a generalized model of cracked fracture was put forward.The Stress distribution of rock mass blasting,relational model of the vibration velocity and stress were studied respectively by the principles of fluid mechanics and fracture mechanics.Based on the sound velocity criterion of the rock mass,the damage threshold of the rock mass is obtained.The calculation model of the damage range of the tunnel is obtained and the critical blasting load and critical vibration velocity of the damage are finally determined.In the aspect of numerical simulation,the dynamic response model of underground stope blasting is established according to the ratio of 1:1 to the production site,the theoretical model of the damage range of blasting rock mass and the dynamic response law of blasting are verified,The results show that in the drilling roadway,the dynamic load is concentrated in the bottom of the tunnel and the middle of the side wall,and the minimum in the vault.In the transport roadway,the dynamic load appears at the bottom and the side wall of the blasting face of the roadway and is the smallest at the vault of the backburst face.The maximum stress appears on the side of the floor close to the explosive source,The blasting load first appears stress amplification in the radial direction of the roadway and then gradually attenuates.By processing the data of vibration velocity and blasting stress of surrounding rock,it is found that there is a strong linear relationship between dynamic load and vibration velocity caused by blasting.In the aspect of outdoor experiment,the vibration velocity of the transportation roadway at the production site was measured first,and the results were compared with the numerical simulation of the vibration data;in accordance with the ratio of 1:40 to establish a small-size concrete model in the model of injury.In the experiment,the calculation model of the damage range,the model of the relationship between vibration and stress and the stress distribution in the roadway were verified.By comparing the blasting vibration and the stress of the corresponding measuring point after the test,the vibration velocity and the dynamic load produced by the blasting have a strong linear relationship,which is consistent with the theoretical research and numerical simulation.Through the analysis of the 'stress distribution,the dynamic load on the profile of the roadway can be concentrated at the bottom and the side wall of the blasting face of the roadway,and the minimum at the vault of the backburst,However,on the extended surface of the surrounding rock to the roadway,due to the different distance from the explosive source and the influence of the shape of the roadway,the stress variation of each extension surface is different.